Apparatus for cutting vegetation

ABSTRACT

Apparatus for cutting vegetation with a rotating head having a ball member portion and carrying non-metallic cutting line extended into the cutting plane by pushing the ball member against the ground while rotating the head. The ball member portion moves inwardly and a spool carrying coiled cutting line forces a predetermined length of line out of the head. After the cutting line length is extended, the head is secured automatically to the spool for further rotation with the driven spool. A cover is releasably secured to the head by a twist-lock connection to allow the spool to be removed from the head for rewinding, etc. Movement of the spool with respect to the head is regulated by uniform interlocking, straight teeth that are rugged, long wearing and provide positive control without any possibility of &#34;free wheeling&#34; with respect to the spool and the head.

This is a division of application Ser. No. 934,226, filed Aug. 15, 1978,and now U.S. Pat. No. 4,189,833 which issued Feb. 26, 1980.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the cutting of vegetation and moreparticularly, it relates to the cutting of vegetation using a flexible,non-metallic cutting line extending from a rotating head into a cuttingplane.

2. Description of the Prior Art

Various types of devices have been proposed for many years to facilitatethe removal of vegetation by mowing, trimming, edging and like cuttingoperations. In general, these devices have employed a metal blade toeffect vegetation removal. Devices of this nature employ prime moverssuch as electric and gasoline motors. As a result, rotating metal bladescan inflict serious and terrible injury upon the user.

In about 1960, there was developed in Europe a trimmer/edger unitemploying a flexible polymeric line extending from a rotating head forcutting vegetation. This unit did not work properly because of severaldefects in structure and operating parameters. In the United States ofAmerica, practical vegetation cutting devices using flexible,non-metallic lines carried upon a rotating head were developed. Thedevices are shown in U.S. Pat. Nos. 3,708,967, 3,826,068, 3,859,776,4,035,912, 4,052,789, 4,054,992 and 4,067,108. These patented deviceshave met outstanding success in that these American developments areprobably the safest electrical or gasoline-powered tools yet inventedfor vegetation cutting, edging and trimming operations.

The devices shown in these patents employ a flexible cutting line, suchas manufactured from Nylon polymer. The cutting line is carried usuallyupon a spool internally of a rotating head. When desired to replenishthe line or to extend an additional length of it, the rotation of thehead was stopped and line manually extended from the spool. This lineextension procedure in the patented devices has been found to beconvenient, simple and reliable. In many of the more powerful devices,especially those powered by d.c. electric motors, a system to extend thecutting line from the head without interrupting cutting operations wasdesired.

One attempt to solve the above problem has been set forth in BelgianPatent No. 852,150, and wherein there is provided a spool movableupwardly during vegetation cutting by contact with the ground of a ballmember connected to the spool. Upward movement of the spool frees thespool from its rotational movement with the head member and centrifugalforce pulls a predetermined length of fresh cutting line from the spoolfor extension into the cutting plane. After the feeding operation, thespool moves downwardly and is again locked to the head member forrotation therewith.

The device of the Belgian patent, while providing a vegetation cutterthat will replenish new line during a cutting operation, neverthelessrelies upon centrifugal force to feed the line which force is at bestunreliable.

The present invention is a device for cutting vegetation in the natureof the above patented devices, wherein a durable and reliable, positiveclutch-like mechanism is employed for extending selectively, the cuttingline in a certain length from the head. More particularly, this novelapparatus is easy to operate, rugged in construction and has nocomplicated mechanisms. A ball portion on the head is depressed whilethe head is rotating. The line is forced from an internal spool which isrotated at a predetermined speed and therefore the spool is underpositive control before, during and after the cutting line is extended.Other unique features of the present invention will be apparent from thefollowing description.

SUMMARY OF THE INVENTION

In accordance with this invention, there is provided an apparatus forcutting vegetation which has a spool rotatable about an axis ofrotation. The spool carries upper and lower planar clutch surfaces. Ahead is carried on the spool and journaled for rotation about therotational axis and adapted to move axially against a biasing means froma first station to a second station. The head has upper and lower planarclutch surfaces. A flexible, non-metallic cutting line is coiled aboutthe spool and has a free end extending outwardly of the head into acutting plane. A ball member portion is mounted for axial movement andextends axially from the head. A plurality of uniform, radial, andangularly spaced straight teeth are carried on the clutch surfaces ofthe spool. The teeth on the clutch surfaces are not radial but aredirected in a fashion to be tangents to a circle of a diameter equal tothe width of the teeth on the spool. The teeth provide selectiverotation of the head in a predetermined angular displacement about thespool in response to the ball member moving the head between the firstand second stations. Positive rotation of the spool force feeds acertain predetermined length of cutting line through the head into thecutting plane. Then, the head is secured again positively for rotationwith the spool.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view illustrating one embodiment of the apparatusfor cutting vegetation arranged according to the present invention;

FIG. 2 illustrates in enlargement the lower portion of the apparatusshown in FIG. 1;

FIG. 3 is a vertical section, in enlargement, taken through the cuttinghead of the apparatus shown in FIG. 2;

FIG. 4 is a top view of the upper cover member of the rotatable headassembly shown and depicted in FIG. 3;

FIG. 5 is a bottom view of the upper cover member of the rotatable headassembly shown and depicted in FIG. 3;

FIG. 6 is a top view of the spool of FIG. 3 and including the foam bandassembly;

FIG. 7 is a bottom view of the spool of FIG. 3 and including the foamband assembly;

FIG. 8 is a side view of the spool-band assembly of FIGS. 3, 6 and 7;

FIG. 9 is a top view of the head member of the rotatable assembly shownand depicted in FIGS. 2 and 3; and

FIG. 10 is an isometric view of an exploded assembly drawing of the headand spool assembly and including the cover, the spool-band unit, thebiasing spring means, and the lower head member.

DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to FIG. 1 there is shown an apparatus for cutting vegetation,which is constructed in accordance with one embodiment of the presentinvention. In this particular embodiment, the apparatus is a grasstrimmer 11, but it could be a lawnmower, edger or other device forvegetation cutting purposes. The trimmer 11 has a lower housing 12interconnected by a tube 13 to a handle assembly 14. The assembly 14provides a switch 16 for selectively applying electrical power receivedby a cord 17 to an electrical motor carried within the housing 12. Fortwo-handed operation of the trimmer 11, an auxiliary handle 18 isprovided upon the tube 13. The lower housing 12 carries a head 19rotatable about an axis passing through the housing 12 and extends thecutting line 21 into a cutting plane which is substantiallyperpendicular to the axis of rotation of the head.

In FIG. 2, there is shown an enlargement of the housing 12 carrying aplurality of air induction openings 22. These openings introduce a flowof cooling air over the prime mover contained in the housing 12. Thehousing 12 includes an electric motor 23 which has adownwardly-extending drive shaft 24. The head 19 is threadedly connectedto the shaft 24 by an integral adapter 99. The upper surface of the head19 may be surrounded by a plurality of vanes 27 serving as a centrifugalblower for moving air radially outwardly from the head 19 during itsrotation. As a result, the induced flow of air cools the motor 23 withinthe housing 12. The head 19 includes a cover 25 and a cylindrical hubportion 98 which includes a curved bump surface 26. The hub 98 carriesin its side peripheral surface an aperture through which the cuttingline 21 extends radially outwardly into the cutting plane. A metalbearing or grommet 28 encircles the aperture and protects the line 21against undue wear and breakages. The cover 25 is releasably secured tothe hub 98. A twist-lock interconnection may be used which includes alug 29 on the hub and a "L" notch 31 on the cover.

The housing 12 includes a rearwardly-extending tail part 32 which servesas a protection to the user to prevent inadvertent contact with therotating cutting line 21. Also, the tail part provides an automaticlimit to the extension of the cutting line 21 from the head 19. Moreparticularly, the tail part 32 has a downwardly-extending projection 33in which is embedded a metal cutting blade 34. As a result, the cuttingline 21 rotated in a cutting plane by the head 19 can never have anoperating length greater than the distance from the axis of rotation tothe cutting blade 34. Any greater length of cutting line isautomatically severed by the blade 34.

The head 19 as seen in FIG. 3, has a smooth peripheral side surface 98carrying the grommet 28 through which the cutting line 21 extends intothe cutting plane. If more than one cutting line is used, each lineshould have a separate aperture and bearing surface. The assemblycarries integrally an adapter 99 in which the drive shaft 24 is securedby threads 37. In addition, the adapter 99 extends axially a sufficientdimension in the head 19 to form a rigid and integral connection withthe shaft 24. Preferably, the adapter 99 is cylindrical with its upperterminus 38 having a flat circular shoulder 39.

The hub 98 forms a cylindrical cavity in cooperation with a cylindricalcover 25. A spool 42 is disposed within the cavity 41. Preferably thespool 42 is integral with the adapter 99. The cover 25 and hub 98 aremounted for independent rotation about the rotational axis and alsoaxial movement about the spool 42. For this purpose, the spool hasspaced-apart planar flanges 44 and 46, and a central axial opening 97 toreceive spring member 47. The flanges 44 and 46 have circularperipheries and define a line storage area 48.

The central portion of the curved surface 26 of hub 98 includes anupstanding boss member 96 which anchors one end of the spring biasingmeans 47. The other end of the spring 47 extends upwardly within opening97 and bears against a locking nut 95 secured to the lower end ofadapter 99 by screw-threads 94.

In addition to the flanges 44 and 46 of spool 42, the spool includes acentral core portion 93 which has a first upwardly extending bearingsurface 92 and a second downwardly extending bearing surface 91. Surface91 cooperates with lower guide means 90 on surface 26 of hub 98, whilesurface 92 cooperates with upper guide surface 100 on cover 25. Sincethe spool 42 is directly connected to the drive shaft 24 via adapter 99,the spool 42 will rotate directly with and at the same speed of rotationthat motor 23 drives shaft 24. Cover 25 and hub portion 98 includingcurved surface 26 however, are not in direct drive connection to shaft24 but by virtue of cooperating surfaces 92, 100 and 90, 91, mayfree-wheel with respect to both the spool 42 and adapter assembly 99.The bias of the spring 47 provides for the up and down movement of thecover 25 and hub 98 with respect to spool 42 as will be explainedhereinafter.

The spool 42 is wound with cutting line 21 contained in several layers49 between the flanges 44 and 46. The inner end of line 21 (not shown)is secured to the core portion 93 of the spool 42 and the free travelingend 21 of the line extends outwardly of spool 42 and into the cuttingplane through grommet 28. Preferably, the line 21 is wound upon spool 42in the same direction of rotation of the head 19 during vegetationcutting and for reasons explained hereinafter. In any event and byvirtue of winding line 21 in the same rotational direction as head 19,centrifugal force during operation will tend to cause the coils of line49 on spool 42 to unwind from the core portion 93 and accordingly tomove away from core portion 93 towards the inner surface 101 of hub 98.In order to prevent this coil unwinding and to maintain the coils 49tightly about core portion 93, annular sponge belly-band 102 isinterposed between coils 49 and wall 101. Band 102 is preferably of anopen or closed urethane foam material and including 40 micron pores. Theparticular construction of the band 102 is not critical provided,however, that it is both flexible, compressible, and adaptable to resumeits original shape after being compressed. The band 102 is easilyremoved and replaced on spool 42 when the unit disassembled (see FIG.10, for example) and may be arranged free of connection to either coils49 or wall 101. In some instances, ribs 103 may be included on wall 101to cause band 102 to move along with hub 98 or in place of ribs 103 band102 may be glued or otherwise fixed to wall 101. As should be apparentfrom FIG. 3, line 21 passes from coils 49, through band 102 and into thecutting plane.

The exposed surfaces of the head 19, and especially the ball member 26,extend axially from the cover 25 in smooth surfaced contour rounded atthe edges and without substantial projections and recesses capable oftrapping appreciable vegetation. Preferably, the exposed surface of theball member 26 is circular with rounded corners and coaxially alignedwith the axis of rotation of the head 19. Also, the ball member 26closely fits into the central opening in the cover 25. As noted above, aspring 47 is seated against the shoulder 96 and the lock nut 95. Thusly,the hub 98 and cover 25 in normal operation are biased into an outwardor first station position. The ball member 26 can also move axially intoan inward or second station position.

The cover 25 fits loosely in a telescoped relationship over thecylindrical spool surface 92. The looseness in fit of these parts canincrease appreciably during repeated line extensions from the head 19.However, these telescoping elements do not need any special closetolerences in axial or angular bearing functions in the present head.Close bearing tolerences are not required by the unique and ruggedmechanisms for locking the spool to the head and for selectivelyreleasing the head to undergo a certain angular displacement requiredfor a predetermined line extension from the spool.

The ball member 26 and cover 25 together move axially along therotational axis as a unit from the outward station to the inward stationwhen cutting line 21 is extended by rotation of the spool 42 relative tothe hub 98. For this purpose, it is preferred to have the head 19rotating at operative speeds and press the ball member 26 against theground to move the ball member to its inward position. The spool 42continues to rotate relative to the hub 98 and forceably extends cuttingline 21 into the cutting plane. Locking elements for this function havea unique form (1) that secures the spool 42 to the hub 98 when the ballmember is in the outward station; (2) when the ball member is moved tothe inward station, that release the spool to rotate within the hub at ahigher speed and through a predetermined angular displacement forforceably extending a certain length of cutting line from the head intothe cutting plane, and then; (3) secures the spool again for furtherrotation with the hub. This functioning is obtained reliably even thoughthe cover 25 and hub 98 may be relatively loose while rotating andmoving axially about spool 42. The novel locking elements resemble thepositive clutch mechanism of the straight toothed type which interlockswith long straight extending teeth surfaces of uniform height incompression for great strength and ruggedness.

The hub 98 and cover 25 have planar clutch surfaces 56 and 57,respectively normal to the rotational axis. Also, the spool 42 hasplanar clutch surfaces 58 and 59 upon the flanges 44 and 46,respectively, normal to the rotational axis. Thus, clutch surfaces 56and 58 and 57 and 59 face one another in parallel relationship. Aplurality of uniform and angularly spaced straight teeth of uniformheight are carried on these clutch surfaces. Further, these teethoverlap axially when the hub 98 and cover 25 are moved axially betweenthe first and second stations. Also, these teeth are offset angularly sothat the spool 42 rotates relative to the head 19 when the head is movedfrom the first station to the second station.

A plurality of straight teeth forming a preferred arrangement are shownin FIGS. 5 and 9. For example, the clutch surface 56 carries eightuniform and angularly offset spaced lower teeth of which teeth 61-64 areshown. The clutch surface 57 carries an upper group of similar eightteeth of which teeth 66-68 are shown. However, the teeth 66-68 areangularly offset one-half the tooth spacing between the teeth 61-64.

The clutch surfaces 58 and 59 on the spool 42 each carry eight similaruniform and angularly spaced teeth of which teeth 71-74 and 76-79 areshown, in FIGS. 6-7, respectively. The teeth on both clutch surfaces 58and 59 are axially and radially aligned. However, the teeth on clutchsurfaces 56 and 57 do not extend radially through the axis of the shaftbut are offset and are directed along a tangent to a circle drawn aboutthe axis and having a diameter equal to the width of one of the teeth onclutch surfaces 58 and 59. This should be apparent from viewing FIG. 9.It will be noted that none of the teeth 61-64 extend directly along aline drawn through the axis. These teeth, as noted above, are ratheralong a line tangent to a circle the diameter of which is equal to thewidth of teeth 76-79 on surface 59 of spool 42. This offset relationshipof teeth 61-64 and 66-68 is necessary in order for the mating sets ofteeth, that is teeth 71-74/66-68 and 76-79/61-64 to fully abut oneanother along their length when in engagement. If it were not for offsetteeth 61-64 and 66-68, the mating pairs of teeth would engage oneanother at angles one to the other rather than in the abuttingrelationship set forth above.

With the ball member 26 at the outward station, the spool has teeth71-74 engaging the teeth 66-68 on the clutch surface 57 of the cover 25.Also, the spool teeth 76-79 are spaced axially a small distance from theteeth 61-64 on the clutch surfaces 56 of the hub 98.

With the trimmer 11 pressed against the ground during operation, theball member 26 moves upwardly into the inward station and the spoolteeth 76-79 move angularly into abutment with the teeth 61-64 of the hub98 after the spool has rotated the certain angular displacement oroffset between the teeth 61-64 and 66-68. These teeth now secure thehead against rotation relative to the spool. Raising the trimmer 11causes the head to be moved axially to its outward station and aboutspool 52. Now, the teeth 71-74 engage the teeth 66-68 after the spool 42has rotated again a prescribed angular displacement relative to theoffset between the teeth 61-64 and 66-68. Thereby, a certain length ofcutting line 21 has been forceably extended from the spool and then, thehead is secured to the spool against further unintended rotation. Thespool has been forceably rotated in the hub a predetermined angulardisplacement with the ball member moving from the outward station to theinward station, and back again to the outward station. As a result, acertain length of cutting line 21 has been unwound from the directlyrotated spool 42 and extended from the head 19.

The straight teeth carried on the clutch surfaces should be uniform inheight although the height may not be identical for all groups of teeth61-64, 66-68, 71-74, and 76-79. It is preferred that the teeth have aheight or axial dimension such that adjacent teeth remain axiallyoverlapped when the hub 98 is between the first and second station. Inthis arrangement, a very loose fitting cover 25 and hub 98 cannot freewheel around the spool during extension of cutting line.

Best results are obtained when all the teeth of each set aresubstantially identical in size and shape (both angular and axial andradial directed dimensions). Preferably, each set of teeth have abuttingside surfaces which are smooth and aligned in lines parallel one to theother. Also, these side surfaces between engaged teeth should bestraight.

Other self aligning side surface shapes can be used, such as pentagons,polygons of triangles, hexagons, etc. Also, these side surfaces may becomplementary intersected curves such as semicylindrical surfaces. Theonly requirement of these side surfaces is that they are complementary.However, these side surfaces may have straight portions along linesparallel to the rotational axis of the spool and head. Thus, the loosefit between the spool 42 and the hub 98 is not critical because of theunique locking elements provided by the self aligning clutch surface andspecially-shaped, straight teeth. Stated in another manner, the"positive clutch" action of these locking elements provides a rugged andlong lasting system to regulate forceable rotation of the spool 42 inthe head 19. If eight uniformly spaced teeth are used on each clutchsurface, the angular spacing between adjacent teeth is 45 degrees, andthe offset between teeth is 22.5 degrees. The spacings between theteeth, for best results, gives line extensions of between one half andone and one half inches. Preferably, the cutting line 21 is extendedabout one inch when the spool 42 completes its predetermined forcedrotation within the head 19. These stated line extension dimensionsproduce good working of the head 19 and allow excellent dimensionalarrangements of the teeth upon the clutch surfaces.

The locking mechanism of the present apparatus may be activated by (1)stopping the rotation of the spool; (2) manually moving the ball memberto the inward position; (3) pulling upon the cutting line; (4) releasingthe ball member to allow the spool to complete its rotation while yetpulling upon the cutting line; and (5) releasing the ball member toallow the spool to complete its rotation while yet pulling upon thecutting line 21. Preferably, the operation is performed (with theelectric motor 23 rotating the spool) by the operator pressing the ballmember to its inward station against the ground. Then, the operatorraises the head 19 slightly from the ground to remove contact of theball member 26 with the earth's surface. Now, the ball member returns toits outward station. As a result, the extension of the cutting line 21is completed very simply and automatically by the novel structureemployed in the trimmer 11.

The cover 25 can be releasably secured to the hub 98 by any system.Preferably, a twist-lock arrangement is used. For this purpose, as shownin FIGS. 3, 5, and 9, the hub 98 carries one or more lugs 29. Theinterior surfaces of the cover 25 carries "L" shaped openings 31 toallow the lugs 29 axially to enter the cover as it is slipped about thehub 98. The cover 25 is rotated on the hub 98 so that the lugs 29 slideinto the horizontal part of the "L" shaped notch 31 and secure the coverand hub into an integral assembly. Preferably, the cover rotates to lockthe lugs into notch 31 counterdirectionally to the direction in whichthe head 19 rotates during operation. Thus, vibrations during headrotation cannot loosen the cover from the hub 98.

In order to secure the assembly together during shipment, there may beprovided means for connecting the cover 25 and the hub 98 together. Asseen in FIGS. 4, 5, 9, and 10, a cotter pin 200 may be inserted throughaligned openings 201 and 202 in the cover 25 and hub 98 respectively.Prior to assembly of the unit 19 to the shaft 24 of the trimmerapparatus 11 of FIG. 1, cotter pin 200 should be removed as rotation ofthe unit will itself lock the cover and hub together as notedhereinabove.

With reference to FIGS. 9 and 10, a further feature of the presentinvention includes means whereby the head embodiment may be balancedrotationally so as not to transmit unwanted vibrations to the motorshaft 24. Thus, to provide a smooth running and rotationally balancedhead assembly 19, it is necessary to offset the weight attributable tothe grommet 28 and the line extending outwardly thereof. If, forexample, a single cutting line passes outwardly of the periphery of head98 via grommet 28, the mass of the grommet and the peripherallyextending portion of the line will unbalance the head in a rotationalsense. Thus, the head will include a mass that is not offset by acorresponding mass at a location diametrically opposite grommet 28. Toovercome this deficiency, and with reference to FIG. 10, there will beseen balancing rib 300. The balancing rib is located diametricallyopposite grommet 28. Thus, for example, balancing rib 300 balances line21 and the grommet. When the head is assembled for grass cuttingoperation and includes therein a full spool of line, the line isinserted into grommet 28. The line extends outwardly of the grommet andacts as a flail to cut vegetation. Normally, a five to six inch lengthof line is used for cutting operations. However, as noted above, it isthis grommet and section of line that causes head 98 to rotate in anotherwise unbalanced condition. It is therefore the function of thebalancing rib 300 to offset this mass of the grommet and the five or sixinch flail. This is accomplished by constructing the balancing rib of anamount of material equal in weight to the mass of the grommet and theextended flail section of line member 21. This weight of the balancingrib will vary from unit to unit depending, of course, upon variablefactors such as line diameter, line density, length of the flail portionof the line, and the particular materials of construction. Sufficient tosay, however, that the balancing rib 300 has a mass equal orsubstantially equal to the mass of the grommet and the extended cuttingflail portion of line 21.

Although the head 19 in all its elements may be formed of metal, plasticor other material, it is preferred to use rather inexpensive polymericmaterials which are readily fabricated by high-speed molding operations.The spool 42 can carry sufficient cutting line 21 (e.g., 0.065-0.100inch in diameter Nylon polymer) for several years' vegetation cuttingbefore requiring a new supply of cutting line. When desired, the cover25 is readily removed from the hub 98 and the spool 42 rewound orreplaced with another having a fresh supply of the cutting line 21.

As explained hereinbefore, the device of the present invention differsfrom the prior art structures in the feature of providing a positive anddirect drive to the spool rather than to the surrounding head assemblyas has been the case in the past. Thus, in FIG. 3, there is seen thatspool 42 rotates at the same speed as shaft 24 because of its directconnection thereto via adapter 99. The sub-assembly of the head member98 and cover 25 maintains more or less a floating relationship withrespect to the spool 42 enabling the spool to actually force feed freshline out of the head rather than to rely upon the action of centrifugalforce in pulling the line from the spool. This spool forced feeding isaccomplished by providing a speed differential between the spool andcover/hub unit, but with the spool being the controlling element in thesystem. In other words, when the member 26 contacts the ground toinitiate a feeding operation, this very ground contact slows therotation of the hub 98 while the spool goes right on rotating at thesame speed as the motor shaft 24. Since spool 42 is turning at a higherrate than the hub 98, the spool 42 actually forces another increment ofline 21 from the coils 49, through band 102, and out of the grommet inthe wall of hub 98. The amount of line extended is, of course,controlled by the cooperation between the clutch surfaces noted above.When ground contact is removed, the hub 98 again returns for rotation atthe same speed as spool 42. Since a substantial amount of stress isplaced on hub 98 by the so-called "tap-and-go" operation, it isdesirable to strengthen hub 98 as much as possible and therefore aninner circular strengthening rib 320 is provided in the interior ofcurved portion 26 of hub 98. Further strength of the hub 98 is providedby the fact that teeth 61-64 are constructed in a fashion to be integralwith both surface 26 and hub wall 101.

A further feature of the present invention may be seen with referenceagain to FIG. 3 wherein it will be seen that grommet 28 is constructedto be rather loosely fitted in wall 101 of hub 98. This provides theadvantage that the grommet may be removed from the hub 98 and replacedby a new grommet, or that the grommet may be rotated in wall 101 topresent new metal surfaces for support of line 21.

Another advantage of the present construction resides in the fact thatthe biasing means 47 in FIG. 3 is fully shielded along its length bycylindrical surfaces in order to prevent the spring 47 from wobbling ina side-ways direction. Thus, surfaces 90 and 91 shield spring 47 inorder that a more or less constant compression of less than ten poundsper inch may be maintained, and radial spring distortion avoided.

In addition to holding the coils 49 about core 93, belly-band 102 alsofunctions as a safety feature in that in the event line 21 breaks off atthe grommet 28, band 102 will hold line 21 and prevent it fromretracting into hub 98. It is then merely necessary to stop motor 23,grab the broken end of the line held by band 102, and extend the line asoutlined above whereupon the cutting operation may again be resumed.Along this line it is again noted that cutting line 21 is wound on spool42 in the same direction of rotation of shaft 24. This is opposite toprior art devices wherein the cutting line is wound in a directionopposite the shaft rotation and wherein such winding actually tightensthe coils on the core of the spool. By winding as in the presentinvention, this tightening effect is avoided and the line actually tendsto unwind from the spool to forceably assist its ejection from the headassembly. Thus, the drag of the hub surface 26 on the ground providesthe line feeding force whereas in prior devices the drag was of nopositive benefit.

From the foregoing description, it will be apparent that there has beenprovided a novel apparatus for cutting vegetation which provides aconvenient and safe method of extending cutting line as desired by theoperator. It will be understood that certain changes or alterations inthe present apparatus may be made without departing from the spirit ofthis invention. These changes are contemplated by and are within thescope of the appended claims which define the invention. Additionally,the present description is intended to be taken as an illustration ofthis invention.

What is claimed is:
 1. As a subcombination,a spool-like member having acore portion and at least two spaced apart flange portions extendingradially outwardly of the periphery thereof, a flexible non-metallicline member wound in coils about said core portion between said flangeportions, and an annular band of a synthetic plastic foam locatedbetween said flange portions and having the inner surface of said bandin contacting relationship to said coils.
 2. The spool-like member ofclaim 1 wherein said flange portions each have a plurality of straightradial teeth of uniform width and height.
 3. The spool-like member ofclaim 1 wherein said line member is wound in coils about said caseportion in the direction of rotation of said spool-like member.
 4. Thespool-like member of claim 1 wherein said annular band is transversed bysaid line member with its free end ending outwardly of said annularband.
 5. The spool like member of claim 4 wherein said annular band isurethane foam.
 6. As a subcombination, a spool-like member having a coreportion and at least two spaced apart flange portions extending radiallyoutwardly of the periphery thereof,(a) said flange portions each have aplurality of straight radial teeth of uniform width and heighth; (b) aflexible non-metallic line member wound in coils about said core portionbetween said core portion between said flange portion, (c) said linemember wound in coils about said core portion in the direction ofrotation of said spool like member; (d) an annular band of syntheticplastic foam located between said flange portions and having the innersurface of said band in contacting relationship to said coils, and (e)said line member extending through said annular band with said linemember having a free end exterior of said annular band.
 7. Thespool-like member of claim 6 wherein said annular band is urethane foam.